1. Field of the Invention
The present invention relates generally to an electro-photographic toner cartridge, and more specifically to systems for detecting low toner in an electro-photographic toner cartridge using a light beam to detect the presence or absence of toner in the cartridge.
2. Description of the Related Art
Conventional electro-photographic printers comprise a toner cartridge having a chamber therein filled with toner. During the print process, toner is transferred from the chamber to print media thereby decreasing the amount of toner within the chamber over the life of the cartridge. When the toner level in the chamber approaches empty, the print quality may suffer. Ultimately, when the chamber is substantially empty, the printer will no longer be able to transfer images to print media. Accordingly, it is desirable to detect and signal to a user when the toner level within the toner cartridge chamber is low.
If toner low notification occurs too late, print quality may already be suffering. Further, late notification may not provide the user with sufficient time to replace the toner. Conversely, if the notification is too early, ample toner may remain in the cartridge and the user may replace the cartridge prematurely. Accordingly, a method for detecting low toner before print quality suffers without indicating low toner prematurely is desirable.
Given the foregoing, it will be appreciated that a method for detecting low toner in an electro-photographic toner cartridge that signals that the toner is low at an optimum time is preferable.